Main Engine Cut Off

NASA’s Launch Vehicle “Stable Configuration” Double Standard

This issue cropped up yet again in the Commercial Crew hearing in the House yesterday (at the 1 hour, 7 minute, 5 second mark):

Space Subcommittee Chairman Brian Babin (R-Texas): Dr. Sanders, how many launches with a stable configuration should NASA require SpaceX and Boeing to achieve before certification?

Dr. Patricia Sanders, chair, NASA Aerospace Safety Advisory Panel: That’s a very difficult question, thank you. Right now, I believe NASA is planning to require seven launches with that configuration, and we believe that’s an appropriate number. There’s some statistical evidence—that Mr. Gerstenmaier could probably talk to a little bit better than I can—why that is a reasonable number. It is not a totally random number, it is a number that’s predicated on having more than a few, but having a timeframe in which you can actually accomplish those and still get on with certification and make the right risk decision on flying.

This requirement grew out of concerns about SpaceX and how frequently they update the design of Falcon 9. And from where NASA stands, it’s a totally valid concern and requirement.

The problem is that it has very blatantly only ever been applied to SpaceX.

Starliner is flying on top of an Atlas V—a launch vehicle with a long, successful history. But flying crew on an Atlas V requires some changes to eliminate abort black zones—sections of flight where aborts are impossible. And doing that requires adding a second engine to Centaur, the upper stage of the Atlas V.

Dual Engine Centaur is not a new concept—Centaur flew with two engines for most of its history. But the last flight of a Dual Engine Centaur was on February 21, 2002–an Atlas IIIB launching Echostar 7. That launch was the first flight of Common Centaur, which is the version of Centaur flying today on Atlas V.

Now, I’m sure there have been design changes to Centaur in the last 16 years, but let’s say that the Echostar 7 launch counts as Dual Engine Common Centaur’s first flight. Then we have to figure out what NASA constitutes a stable configuration: is it a particular variant of a fully-integrated stack, or can first and second stages be flown independently and count towards the stable configuration flight count? From what I’ve gathered, it’s the former.

Starliner’s first flight will be the first flight of the Dual Engine Common Centaur on Atlas V. Starliner’s second flight—its first with crew—will be flying the second.

Two is a long way from seven.

Stacking Mission Extension Vehicles

Really interesting technical note on how Orbital ATK’s Mission Extension Vehicles stack with other satellites in an article by Caleb Henry of SpaceNews:

Intelsat is not the first satellite operator to agree to launch an Orbital ATK-built satellite stacked with the company’s Mission Extension Vehicle. Late this year, the Eutelsat 5 West B satellite will be stacked with MEV-1 for launch aboard an International Launch Services Proton rocket. Both Galaxy-30 and Eutelsat 5 West B are based on Orbital ATK’s GEOStar spacecraft platform.

The ability to directly stack MEVs with GEOStar satellites gives Orbital ATK a new selling point. Because one side of the MEV is devoid of crushable instruments, a satellite can be stacked on top of it without using the protective barrier Ariane 5 normally places between dual-launched satellites. Stacking MEV with a GEOStar satellite enables dual launch on rockets that have no divider, like Proton, or, in the case of MEV-2, enable a third passenger to share the cost of a launch.

T+70: Polar Launches from Cape Canaveral

The US Air Force has developed a viable corridor for launching to polar and other high-inclination orbits from Cape Canaveral. I spend some time thinking through who may be interested in using that corridor and what its existence could mean for the newer launch vehicles in development.

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Polar XS-1 Launches

In thinking through who may launch to high-inclination orbits from the Cape, I totally forgot about DARPA’s XS-1 that will be based out of Cape Canaveral. I would be surprised if there weren’t plans to launch XS-1 from Vandenberg, but as of yet, we haven’t heard anything. Maybe the Department of Defense had XS-1 in mind when developing a polar corridor from Cape Canaveral?

The trouble there is that XS-1’s payload to orbit is already fairly low—1,360 kilograms—and launching to polar orbits from the Cape will lower that even more. That said, a few hundred kilograms to high inclinations would be competitive with Electron or LauncherOne-class vehicles.

Mars’ Seasonal Methane Cycles

Fascinating piece by Eric Hand, for Science:

In the southern winter, some of that CO2 freezes out onto the large southern polar cap, making the overall atmosphere thinner. That boosts the concentration of any residual methane, which doesn’t freeze, and by the end of northern summer this methane-enriched air makes its way north to Curiosity’s location, Forget says. Seasonal variations in dust storms and levels of UV light could also affect the abundance of methane, if interplanetary dust is its primary source.

But, Webster said at the meeting, the seasonal signal is some three times larger than those mechanisms could explain. Maybe the methane—whatever its source—is absorbed and released from pores in surface rocks at rates that depend on temperature, he said. Another explanation, “one that no one talks about but is in the back of everyone's mind,” is biological activity, says Mike Mumma, a planetary scientist at Goddard Space Flight Center in Greenbelt, Maryland. “You’d expect life to be seasonal.”

Another hypothesis, which has an opportunity to be tested in just a few weeks:

Other scientists are looking skyward. Marc Fries, the cosmic dust curator at Johnson Space Center in Houston, Texas, says the source of methane spikes could be the hail of tiny meteors that falls when a planet crosses a comet’s orbit and sweeps up carbon-rich dust and debris shed by the comet. Fries says that as the dust particles vaporize at altitudes of tens of kilometers, the same chemical reaction that produces methane from interplanetary dust at the surface would take place more quickly, driven by the stronger UV light at high altitudes. All the claimed methane spikes over the past 2 decades occurred within about 2 weeks of a known martian meteor shower, Fries and his colleagues found. “It could be a cause, and it could be a coincidence,” he says.

It happens that Fries will have a chance to test the hypothesis. On 24 January, Mars will have a close brush—less than a tenth of the Earth-moon distance—with the orbit of comet C/2007 H2 Skiff. Mumma is skeptical about Fries’s idea, but he will nevertheless be watching for methane with his telescope in Hawaii in the days after the encounter. The MAVEN and Curiosity teams also plan to watch. “This is a great opportunity to test this hypothesis,” Crismani says.

Orbital ATK Signs Cooperative Agreement with U.S. Air Force Space and Missile Systems Center

The CRADA provides the framework and plan for data exchanges needed to certify Orbital ATK’s Next Generation Launch (NGL) system to carry National Security Space missions.

Orbital ATK is currently in early production of development hardware for NGL. To date, the company has jointly invested with the Air Force more than $200 million to develop the NGL rocket family.

The next phase of the NGL program is expected to begin when the Air Force awards Launch Services Agreements in mid-2018, which would entail full vehicle and launch site development

Plans could change, obviously, but the last bit there seems to confirm that Orbital ATK is only going to build this launch vehicle if they are awarded funding from the Air Force in the upcoming Launch Services Agreements.

Intelsat Orders MEV-2 from Orbital ATK

The vehicle was ordered by Intelsat S.A. to provide life extension services for an Intelsat satellite. Orbital ATK is now producing MEV-1, the industry’s first commercial in-space satellite servicing system, for Intelsat with launch scheduled for late 2018. Under this new agreement, Orbital ATK will manufacture, test and launch MEV-2 and begin mission extension services in mid-2020.

Someone over at Intelsat has been doing a lot of math, and it looks like Orbital ATK was serious—the business case closes.

ZUMA, USA 276, and ISS

ZUMA has been wrapped up in the mystery surrounding USA 276 and the ISS since last November, when Marco Langbroek found that its launch window and trajectory lined up very closely to their orbits.

After a few delays (with little insight into their causes, much like the launch of USA 276…), things seem to be lining up again:

The new launch window for January 6th is the same as it was in November: 1:00 UT to 3:30 UT. This excludes a launch (exactly) into either the ISS or USA 276 orbital planes, as the latter only pass over the Florida launch site after the launch window has ended.

This would seem to suggest that the coincidence in time of the launch window and orbital plane passages in November was indeed coincidence (but there is a "but": see below...).

On January 6th, the orbital plane of USA 276 passes over the launch site around 4:27 UT, an hour after the end of the launch window. The orbital plane of the ISS passes over the launch site around 7:04 UT, some 3.5 hours after the end of the launch window.

The launch already has slipped one day, and a few days further delay would slip the passage of the USA 276 orbital plane back into the launch window, as the moment of orbital plane passage shifts about 24 minutes earlier in time each day. This would happen already with a 3-day delay in launch. And a further delay eventually would do the same for the ISS orbital plane passage after several more days.

And the launch has already slipped yet another day since this post.